一种高效的基于模式色散的全光积分器

A cost effective all optical integrator based on modal dispersion

对基于模式色散的全光积分器进行数值仿真和实验研究,实现了一种一维展宽倾斜入射方式的全光积分器。在模式色散的作用下,光信号经过光纤时不同的模式产生了不同的延时,叠加后产生了积分的效果;选用了较大面积的高速光电探测器(PD)接收多模光纤(MMF)的输出光束,利用50m的MMF实现了时间窗口约为1.5ns的全光积分器;最后使用该积分器对光信号进行了积分实验。由于使用模式色散作为产生时延的主要方法,因此方法具有与波长无关的特性,而且能在很短的光纤上获得较大的时间窗口。一维展宽的入射方式具有很好的灵活性,易于调试和控制。

The all optical integrator based on modal dispersion is studied in this paper through numerical simulation and experiment.The numerical simulation shows that the time delay induced by modal dispersion in step-index multimode fiber（MMF）is close to linear.A cost effective method uses a tilted input optical beam in one dimension which is launched into the MMF to excite different modes.Time delay is generated between different modes by modal dispersion as the optical signals are transmitted through the MMF,and the optical signal in different modes can overlap with each other.A large area high speed photodiode（PD）is used to receive the optical signal in different modes.An all optical integrator with time window longer than 1.5ns is achieved in an MMF with length of 50 m.An application of the all optical integrator is demonstrated.Since the system is mainly based on modal dispersion,it′s independent of the wavelength of the optical sources.Its time window is much larger than that of the system based on chromatic dispersion using the same length fiber.Besides that,because of the one dimension stretching before the optical beam launched into the MMF,it has good flexibility.